Owing to the rapid technological development of the semiconductor and software industry, computing devices are now ubiquitous and come in various form factors. Whereas early computers generally were stationary devices which allowed a user to interact with a text-based or graphical user interface mainly via a pointing device, such as a computer mouse, and/or a computer keyboard, modern computing devices are frequently portable devices such as smart phones, tablet computers, hybrids of laptops and tablet computers, etc., and allow user input via a touchscreen. Other modern types of computing devices include TVs with internet access, digital content streaming devices, gaming consoles etc.
A common denominator of the aforementioned user input interfaces is that they generally require the user to make physical contact with the input device using the hand or fingers (e.g. buttons of a keyboard, moving a computer mouse, the surface of a touchscreen, buttons of a remote control or a game controller). As an alternative, input devices allowing a user to control an input operation by making a gesture with the hand have been proposed. For such input devices to become usable and popular they would however need to be reliable in terms of detection and be comfortable to wear. A relatively inconspicuous appearance would also be beneficial. US 2004/0243342 discloses a user input apparatus in the shape of a wrist watch or bracelet and suggests that gestures may be detected by electrically sensing a change of the shape of the wrist.